1. Field of the Invention
The present invention relates to an emergency calling via a cable modem. More particularly, the cable modem is connected to a Public Switched Telephone Network (PSTN), in response to an emergency telephone number received from a subscriber via a telephone line, to transmit a calling signal corresponding to the received emergency telephone number to the PSTN via a PSTN backup line connected to the cable modem.
2. Description of the Related Art
In general, a modem is constructed to transmit and receive data via a telephone line, whereas a cable modem is connected to a cable network via a coaxial cable to allow a link to the Internet. Current cable modems in the cable network support a transmission rate of about 30 Mbps.
In such a cable modem-based Internet telephone service, there is global demand for an emergency calling function to be carried out via a PSTN backup line and the stable TSTN.
However, there is a problem in that conventional emergency calling service via a cable modem cannot promptly cope with an emergency since it transmits an emergency call signal to a (Cable Modem Terminal System) CMTS via the cable modem and then to a backbone network via the CMTS, thereby consuming a long time delay before an emergency call is linked.
U.S. Pat. No. 6,393,104 to Akhteruzzaman et al., entitled ENHANCED LIFE-LINE SERVICE FOR CABLE TELEPHONE CUSTOMERS, issued on May 21, 2002, which relates to an arrangement for enhancing the capabilities of emergency service provisions for telephone stations served by a cable system. In accordance with the prior art, telephone stations served by cable systems are frequently provided with access to an emergency telephone line for making emergency calls when the cable system lacks power, or is otherwise inoperative. In accordance with this invention, the emergency service line is used for making incoming calls directed to all telephones connected to the emergency line, using a different telephone number for the emergency call. Outgoing service is also provided to the telephones connected to the emergency line. Advantageously, the value of the emergency line service is substantially enhanced.
U.S. Patent Application No. 2002/0001367 to Lee, entitled COMPUTER HAVING EMERGENCY CALLING FUNCTION AND EMERGENCY CALLING METHOD USING COMPUTER, published on Jan. 3, 2002, which disclosed that, in a computer having an emergency calling function for detecting an emergency situation and for transferring an emergency call message previously set by a user to a preset emergency call telephone number, a non-volatile memory stores information which is not lost if power is turned off. A message/telephone number setter receives an emergency call message indicating an emergency situation and an emergency call telephone number which are input by a user and stores the received message and number in the non-volatile memory. An emergency call button generates an emergency detection signal when the user presses an emergency call button. A microprocessor receives the emergency detection signal from the emergency call button and restores the computer from a power-save state or a power-off state to a normal state. An emergency call controller reads the emergency call message and emergency call telephone number from the non-volatile memory and makes a telephone call to the emergency call telephone number to transfer the emergency call message, after an operational state of the computer has been restored to a normal state by the microprocessor.
U.S. Patent Application No. 2003/0202462 to Smith et al., entitled METHOD AND APPARATUS FOR FAIL OVER PROTECTION IN A VOICE OVER INTERNET COMMUNICATION SYSTEM, published on Oct. 30, 2003, which discloses that, in a packet data communications system (100) that supports VoIP communications via cable modem, a fail over detector (200) identifies trouble (eq, no dial tone, delayed dial tone, low quality of service, no voltage, no current, network busy) on or within the communications path. In response, voice communications are switched to a secondary path, such as, for example, the PSTN, or some other reliable and/or predictable communications network, thereby insuring uninterrupted voice communications.
U.S. Pat. No. 6,587,546 to Stumer et al., entitled METHODS AND APPARATUS FOR DIALING AN EMERGENCY TELEPHONE NUMBER FROM A TELEWORKING CLIENT REMOTELY COUPLED TO A PBX, issued on Jul. 1, 2003, which relates to methods for dialing an emergency telephone number from a teleworking client according to the invention include detecting at the teleworking client when an emergency number is dialed, disconnecting the teleworking client from the PBX/MLTS, connecting the teleworking client to the PSTN, and dialing an associated stored number. The apparatus of the invention resides in software that is installed in off the shelf hardware. Though the invention is described with reference to a teleworking client, it may also be applied to any other dialup network connection
U.S. Pat. No. 6,678,356 to Stumer et al., entitled SYSTEMS FOR DIALING AN EMERGENCY TELEPHONE NUMBER FROM A TELEWORKING CLIENT REMOTELY COUPLED TO A PBX, issued on Jan. 13, 2004, which relates to systems for dialing an emergency telephone number from a teleworking client according to the invention include apparatus that implement the steps of detecting at a teleworking client when an emergency number is dialed, disconnecting the teleworking client from the PBX/MLTS, connecting the teleworking client to the PSTN, and dialing an associated stored number. Though the invention is described with reference to a teleworking client, it may also be applied to any other dialup network connection.
U.S. Patent Application No. 2002/0136358 to Stumer et al., entitled SYSTEMS FOR DIALING AN EMERGENCY TELEPHONE NUMBER FROM A TELEWORKING CLIENT REMOTELY COUPLED TO A PBX, published on Sep. 26, 2002, which relates to systems for dialing an emergency telephone number from a teleworking client according to the invention include apparatus that implement the steps of detecting at a teleworking client when an emergency number is dialed, disconnecting the teleworking client from the PBX/MLTS, connecting the teleworking client to the PSTN, and dialing an associated stored number. Though the invention is described with reference to a teleworking client, it may also be applied to any other dialup network connection.
U.S. Patent Application No. 2002/0136359 to Stumer et al., entitled METHODS AND APPARATUS FOR DIALING AN EMERGENCY TELEPHONE NUMBER FROM A TELEWORKING CLIENT REMOTELY COUPLED TO A PBX, published on Sep. 26, 2002, which relates to methods for dialing an emergency telephone number from a teleworking client according to the invention include detecting at the teleworking client when an emergency number is dialed, disconnecting the teleworking client from the PBX/MLTS, connecting the teleworking client to the PSTN, and dialing an associated stored number. The apparatus of the invention resides in software that is installed in off the shelf hardware. Though the invention is described with reference to a teleworking client, it may also be applied to any other dialup network connection.
The following patents also each discloses features in common with the present invention but do not teach or suggest the inventive features specifically recited in the present application: U.S. Pat. No. 6,029,047 to Ishida et al., entitled CABLE TELEPHONY TERMINAL DEVICE HAVING A CALL LINE SELECTOR, issued on Feb. 22, 2000; U.S. Pat. No. 5,999,612 to Dunn et al., entitled INTEGRATED TELEPHONY AND DTA SERVICES OVER CABLE NETWORKS, issued on Dec. 7, 1999; U.S. Pat. No. 5,034,948 to Mizutani et al., entitled TELEPHONE APPARATUS SYSTEM, issued on Jul. 23, 1991; U.S. Pat. No. 6,570,974 to Gerszberg et al., entitled CABLE CONNECTED NETWORK SERVER PLATFORM FOR TELEPHONE WHITE-YELLOW PAGE SERVICES AND EMERGENCY 911 LOCATION IDENTIFICATION, issued on May 27, 2003; U.S. Pat. No. 5,999,612 to Dunn et al., entitled INTEGRATED TELEPHONY AND DATA SERVICES OVER CABLE NETWORKS, issued on Dec. 7, 1999; U.S. Patent Application No. 2003/0093563 to Young et al., entitled METHOD AND SYSTEM FOR IMPLEMENTING AND MANAGING A MULTIMEDIA ACCESS NETWORK DEVICE, published on May 15, 2003; U.S. Patent Application No. 2003/0043974 to Emerson III, entitled STORED PROFILE SYSTEM FOR STORING AND EXCHANGING USER COMMUNICATIONS PROFILES TO INTEGRATE THE INTERNET WITH THE PUBLIS SWITCHED TELEPHONE NETWORK, published on Mar. 6, 2003; U.S. patent application No. 2003/0210766 to Lin et al., entitled INTELLIGENT MANAGEMENT SWITCH WITH EMERGENCY CALLING FUNCTIONALITY, published on Nov. 13, 2003; U.S. Pat. No. 6,614,884 to Jang, entitled, AUTOMATIC HOME ALARM SYSTEM AND METHOD, issued on Sep. 2, 2003; and U.S. Patent Application No. 2003/0035514 to Jang, entitled AUTOMATIC HOME ALARM SYSTEM AND METHOD, published on Feb. 20, 2003.